(a) Content generally.

1. (1) A petition for leave to intervene must set forth:

   1. (A) The grounds of the proposed intervention;
   2. (B) The position and the interest of the petitioner in the proceeding; and
   3. (C) Whether petitioner's position is in support of or opposition to the relief sought.
2. (2) If the proceeding be by formal complaint and affirmative relief be sought by petitioner, the petition should conform to the requirements for a formal complaint.

(b) When filed.

1. (1) A petition for leave to intervene in any proceeding should be filed not less than twenty (20) days after the official date of filing, except for good cause shown.
2. (2) Such intervention must show service of a copy on the interested parties or their attorneys by registered or certified mail with return receipt required.
3. (3) The return receipt or a photocopy thereof must be filed with the State Highway Commission by said intervener.

(d) Disposition.

1. (1) Leave will not be granted to intervene except on averments reasonably pertinent to the issues already presented and which do not unduly broaden them.
2. (2) If leave is granted, the petitioner thereby becomes an intervener and a party to the proceeding.